NR 811.853(2)(f)(f) The filter shall be located in an area not subject to flooding, and the site shall be graded to prevent ponding of surface runoff. Finished grade elevation shall be designed to facilitate maintenance, cleaning, and removal or replacement of surface sand. An overflow may not be provided.

NR 811.853(2)(g)(g) The filtrate shall be discharged to a sanitary sewer, water of the state, or holding tank and shall meet the provisions under s. NR 811.85 (1).

NR 811.853(3)(3) Discharge to lagoons. Lagoons used to settle backwash wastewater from iron and manganese removal filters shall meet all of the following design requirements:

NR 811.853(3)(a)(a) Lagoons shall be designed with a volume which is 10 times the total quantity of wastewater discharged during any 24-hour period.

NR 811.853(3)(b)(b) Lagoon length shall be 4 times the width, and the width shall be at least 3 times the depth. The minimum useable depth shall be 3 feet.

NR 811.853(3)(e)(e) The lagoon effluent shall be discharged to a sanitary sewer, water of the state, or holding tank and shall meet the provisions under s. NR 811.85 (1) or shall be returned to the water treatment plant in accordance with the requirements under s. NR 811.862.

NR 811.853(4)(4) Discharge to detention tanks. Detention tanks used to settle backwash wastewater from iron and manganese removal filters shall meet all of the following design requirements:

NR 811.853(4)(a)(a) Detention tanks shall be designed to maximize settling by means of inlet piping and baffling configurations. Tanks shall be of sufficient capacity to hold at least 2 complete backwash cycles. The floor shall be sloped to a sump and access manholes provided to facilitate cleaning. A cover shall be provided to prevent freezing.

NR 811.853(4)(c)(c) The detention tank supernatant shall be discharged to a sanitary sewer, water of the state, or holding tank and shall meet the provisions under s. NR 811.85 (1) or shall be returned to the water treatment plant in accordance with the requirements under s. NR 811.862. If discharged to a water of the state, pumps shall be provided to discharge the supernatant over approximately a 24-hour period.

NR 811.853(4)(d)(d) Settled sludge removed from detention tanks shall be disposed of at a wastewater treatment plant unless the department approves an alternate disposal location on a case-by-case basis. The disposal of sludge shall meet the applicable requirements under s. NR 811.85 (1).

NR 811.853 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: cr. (intro.), am. (1), (2) (a), (d), r. and recr. (2) (g), am. (3) (b), r. and recr. (3) (d), cr. (3) (e), am. (4) (b), r. and recr. (4) (c), am. (4) (d) Register January 2024 No. 817, eff. 2-1-24.

NR 811.854NR 811.854 Brine wastes from ion exchange plants. Brine wastes from ion exchange processes may be discharged to a water of the state subject to the requirements under s. NR 811.85 (1) (b). An equalization tank of sufficient size to allow brine discharge over at least a 24-hour period shall be provided. The department may approve a smaller tank or no equalization if the water system facility demonstrates to the department that reduced equalization is unnecessary to prevent toxicity to aquatic life.

NR 811.854 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: r. and recr. Register January 2024 No. 817, eff. 2-1-24.

NR 811.855NR 811.855 Wastewater from reverse osmosis plants. Reject, backwash, and concentrate wastewaters from reverse osmosis processes may be discharged to a water of the state subject to the requirements under s. NR 811.85 (1) (b). Chemical cleaning waste shall not be discharged to a water of the state. An equalization tank of sufficient size to allow discharge over at least a 24-hour period shall be provided for a surface water discharge. The department may approve a smaller tank or no equalization if the waterworks facility demonstrates to the department that reduced equalization is unnecessary to prevent toxicity to aquatic life.

NR 811.855 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: r. and recr. Register January 2024 No. 817, eff. 2-1-24.

NR 811.856NR 811.856 Water treatment plant wastewater radionuclide content compliance with the unity equation. Water treatment plant wastewater containing radium or uranium shall not be discharged to a sanitary sewer or to waters of the state unless all of the following requirements are met:

NR 811.856(1)(1) Unity equation. The levels of radium and uranium in the wastewater shall meet the limits of the Unity Equation as calculated based upon the requirements of the department of health services under s. DHS 157.30 (3) and Appendix E of ch. DHS 157.

NR 811.856(2)(a)(a) Unity equation calculations in accordance with sub. (1) shall be performed for water treatment plants treating wells with combined radium-226 and radium-228, uranium, or both, exceeding the maximum contaminant level. The department may require unity equation calculations on a case-by-case basis if other radionuclides may be of concern.

NR 811.856(2)(b)(b) The water system owner or its consultant shall submit the Unity Equation assumptions and calculations to the department for review and approval before, or along with, the submission of plans and specifications to the department for the radionuclide removal water treatment equipment or plant.

NR 811.856(3)(3) Corrective actions. Corrective action as approved by the department shall be taken, if necessary, to maintain the result of the Unity Equation calculations as less than one.

NR 811.856 NoteNote: The department’s Public Water Supply Section located in Madison may be contacted to obtain a copy of DNR Application of DHS Radionuclide Wastewater Disposal Criteria for help in addressing Unity Equation issues.

NR 811.856 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (1) made under s. 13.92 (4) (b) 7., Stats., Register November 2010 No. 659; CR 22-074: r. and recr. (intro.), am. (2) (a) Register January 2024 No. 817, eff. 2-1-24.

NR 811.857NR 811.857 Backwash wastewater from lime softening water treatment plants. Filter backwash wastewater from lime softening water treatment plants shall be disposed of by any of the following methods: